This invention relates to the field of cooling systems for electronic components and, more particularly, to the use of heat pipes to cool electronic circuit board components.
In many electronic systems, such as large scale digital computers, the efficient cooling of electronic components is becoming an increasing problem. With the advent of large scale integrated circuit modules containing many thousands of transistors, it has become possible to pack vast numbers of electronic components together within a very small area. However, these integrated circuit modules, during the course of their normal operation, generate significant amounts of heat. Since most solid state devices are sensitive to excessive heat, the generation of heat by the large scale IC's in close proximity to one another has become of increasing concern to industry. A typical approach to cooling components in digitial computer systems, where the modules containing integrated circuits are placed on circuit boards, is to direct a stream of cooling air across the modules and the boards. One of the principal disadvantages of this approach is that the air, as it passes down a row of circuit cards, progressively increases in temperature as it absorbs heat from the boards and, as a result, loses much of its ability to absorb heat from the circuit boards at the end of the row. Cooling the components by this means necessitates a number of compromises to the overall system, such as: placing the modules containing the integrated circuits farther apart on the circuit boards; increasing the distance between circuit boards; and increasing the volume and velocity of cooling air directed over those components which, of course, requires special considerations in the design of the cabinets containing the circuit boards and the mechanical systems for delivering the air.
With increasing emphasis on high speed operation in electronic systems such as digital computers, it has become increasingly desirable to place the electronic components physically as close as possible to one another. In addition to facilitating the packaging and the structure of the overall system, close placement of the integrated circuit modules, especially in high speed digital computers, is highly desirable due to significant propagation delays in electronic signals resulting from the physical separation of the modules. In addition, in order to get the various electronic components in an integrated circuit to operate at higher speeds, it is necessary to apply more power to the components which, in turn, means that more heat is generated. The problem of removing the heat generated by the integrated circuits has led to compromises with respect to the design speed of various types of electronic equipment.